Question

I am developing an iPhone app and I have a problem accessing to one NSArray defined on delegate.

My app has two tabs. These two tabs have an UITableView. I have the source of the data of these tables on one NSArray defined in the delegate.

When I load the application, the first tab loads correctly all the content. This is one part of code of the first tab controller:

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    // Return the number of rows in the section.
    mainAppDelegate *delegate = [[UIApplication sharedApplication]delegate];
    return [delegate.dataArray count];
}

When the debugger is on return statement, I can see that dataArray has 9 elements. The code works fine.

When I click on the second tab, the same code is executed in the second’s tab controller. But while debugger is on return statement, I can see that delegate is not null and dataArray shows

{(int)[$VAR count]} objects

On next step, program crashes giving EXC_BAD_ACCESS

I think in this point dataArray has been released, but I don’t know when. I have deleted dataArray release calls on dealloc functions.

This is the property definition of dataArray:

@property (nonatomic, retain) NSArray *dataArray;

Anyone has any idea? I’m completely lost on it. Thanks for your help!

Answer 1

As per your comment, you initialize your array like this:

 dataArray = [dict objectForKey:@"data"];

This does not retain the array since you are accessing the ivar directly, not the property. You should do this instead:

self.dataArray = [dict objectForKey:@"data"];

Some programmers prefer to synthesize their properties with a different ivar name to avoid such mistakes.

@synthesize dataArray = dataArray_;